On the left is
the real Soundtracs Topaz PSU & on the right is my Transformer
replacement.

I
consider my Soundtracs Topaz recording console the center piece in my
home studio, maintaining & keeping it functioning has had it's
challenges. Using a schematic available fromThe
Soundtracs Guy. Seen here on this page are pictures
of the two replacement transformers I made for my Soundtracs
Topaz console.The prototype

I built
my first Topaz psu replacement into a open rack mount case. I choose to
hollow out a Behringer
UltraFX because it had XLR sockets (perfect for the Neutrix
connections) already drilled out on it's rear
faceplate.For some of my
wiring, like wiring the power
socket to the terminal block, I use
a common three wire computer power extension cable.I
just cut the ends off and use the cable. I have brought this up,
because you will notice that in my
prototype I used the green wire (ground) to connect the neutral run
from my
power socket to the terminal block. I correct this in the second
enclosure build, and used the
inductry standard white wire for the run in the final project (see pic
below). Sorry if this confuses anyone. This first build was somewhat of
a rush job after my original transformer blew. Argh! I built
this replacement as fast as the parts arrived in the mail. I have a
hard time without
my Topaz working. This prototype had no ON / OFF switch, the circuit
was plugged into a power strip which had the power switch.

*
WARNING *

Please
safely secure an open rack transformer like this. This can be a real
electrical hazard. DO
NOT TOUCH or HANDLE a powered transformer.

Power Strips & Surge
Protectorscan
serve as both power switch and fuse box. A quick and easy solution when
prototyping a power related device.

Notes
on this parts
list ...I over purchased because I
made two versions of the Soundtracs Topaz PSU;
a
rackmount and a
portable unit.

Suggest
purchasing the 1/8" heat shrink
tube insulation for the internal power connections.

For wiring the power
socket to the terminal block, I used a
spare common
three
wire computer power extension cable.

Building
the XLR
cable

Building
the XLR cable is a straight job. Each of the Neutrik XLR 4 pins is
labeled on the connectors. Labeled by the solder buckets on the inside
of the Neutrik connectors, you will read 1, 2, 3, 4. You will need a
soldering iron to join these two Neutrik
connectors by 10 feet / 3 meters of 4 conductor 18 awg wire. Solder to
each end of the
four wires in your 4 wire cable, 1 Neutrik XLR Male
Connector to one end & 1 Neutrik XLR Female Connector to the
other
end. The Heilsound
wire that I used is color coded. So I identified
each of the four individual colors within the Heilsound 10 foot / 3
meter cable to the
Neutrik pins found on the connectors. The maximum length for the cable
is 10 feet / 3 meters. In both of the transformer replacement example I
have presented on my webpage, I cut the cable length to 9
feet. I
used 1 foot of my Heilsound cable for
connecting the Neutrik female socket of the
PSU to the terminal block, seen in the pics below.

You will not be able to exceed 10 feet / 3 meters on your connecting
cable's length. Cables exceeding 10 feet / 3 meters will experience a
voltage drop and
the console will not power up. I have made two of these cables in my
efforts, a 5' and a 9.5'. From the Heilsound 10' cable that you
purchase you can use 1 foot - 1/2 foot of the cable for the PSU's
internal
connections. This will also visually help you line up the circuit
correctly through the wire's identification colors.

Building the PSU

The
following pictures were made during the building of this PSU unit. I
used crimp connectors on all the wires connecting to the terminal
block.

blue
& violet wires of the transformer need to be connected to BLACK
(HOT) wire to your power outlet.gray
& brown wires of the transformer need to be connected to the
WHITE(Neutral) wire to your power outlet.
Orange,
Yellow, Black & Red wires of the transformer need to be
connected
to their cooresponding wires of the XLR cable run that will eventuall
connect your replacement transformer to your Topaz' XLR power
connection on the rear of the mixer.

(seen in the picture above)

I
used crimp connectors on all the wires of the Toroidal transformer
& screw mount attach them to the terminal block. Then I crimp
connected one
end
of the 1 foot I cut from the HeilSound
& soldered the other end
of
my HeilSound
cable to the Neutrik female socket. pictured below. The
toroidal's primaries (115v); blue & violet, gray &
brown(see picture above) as
well as
the power mains to the power socket (Black & white in picture
above) are crimp connected and screw mounted to the terminal
block. Using a terminal block is great in this application,
making an easy job if I ever have to replace the transformer.

From
the rear of my PSU enclosure: Female Neutrik socket "LEFT", power
socket "RIGHT". Probably
over kill was the binding post I used to wire the ground "GREEN", of
the power socket to.
Please note the picture above was taken before the rear panel faceplate
was installed. In
order to completethis
project these components, the XLR socket & power
socket must be mounted to the rear faceplate and then wired
correctly back to the terminal block, and the ground of the power
socket needs to then be wired to the binding post. Leave yourself some
slack in the connection wires.

This
next picture
shows the wiring up of the switch. I used an illuminated ON / OFF
switch I bought from Digikey. I drilled the hole into the front panel
of the enclosure using a stepper drill bit on my drill press. This
project was made in part by me having a drill press. Without it,
mounting the switch would have been a problem and drilling
without
a stepper drill bit in this application will no doubt drill a jagged
hole in your panel and possible ruin your enclosure. Also seen here in
this picture is the metal plate that the transformer is mounted on. The
riser in my enclosure is made of steel and without a drill press would
be a real nightmare to drill. See how I elevated this deck plate that
the transformer is mounted on for wiring purposes and keeping the
central spoke of the toroidal centered, locked in and not touching
anything. For these enclosures sold through DigiKey there is a central
elevated riser piece that you can purchase. But in my design the Bud
Industry riser put the transformer to high & created problems
when
considering the back of the XLR socket. So I went with making my own
riser for this enclosure project.
With enough nuts & bolts I can adjust the riser to any height.
I
also used my drill press for the needed holes through the bottom of the
enclosure that connects the riser to the bottom of the enclosure.

As
far as choosing the right fuse to work with this DIY transformer, mine
is mounted internally, between the power socket & switch. If
your
transformer will be just powering a Topaz 24-32 channel mixer without
the meterbridge, use a 2-2.5Amp Fast Blow. If your Topaz has the
meterbridge connected use a 3.15Amp Fast Blow.

The
last part to my project was adding the internal fuse box, & not
out
of consideration to the original schematic. I
plug all of DIY circuits and builds directly into an isobar which has a
circuit breaker fuse. That is connected to a UPS which has a fuse
breaker.
With any and all DIY home built transformers or self powered devices I
highly recommend that you DO NOT EVER
plug directly into the wall.Unless
you feel very secure about the surge protection, current flow &
outlet's breaker you are plugging into. So put a fuse on it or always
plug into a surge protector.

Last, at
different
stages while building this transformer circuit. You certainly will want
to test. Please again, plug into a power strip / surge protector.
Always have a surge protector on the wall outlet. If your power strip
has a built in surge protector, even better. If you have incorrectly
wired something in your transformer circuit or improperly grounded the
transformer, it will trip the circuit. Easily fixed at the breaker, but
if you are testing your transformer project in a room with other
electronics and you blow the rooms circuit, everything will power off.
Given what was on in your room / studio, this might be upsetting. So be
safe & happy; when testing, using and enjoying your replacement
transformer,
always plu into a power strip / surge protected AC wall outlet.
The end result is a small well vented portable Toroidal transformer for
the Soundtracs Topaz.
Works Great!

There are numerous mixers that have been manufactured over the years,
that employ the use of an external transformer. They have their
advantages.

Not a Soundtracs owner, but need to replace your external PSU.
With a few changes you might find that this transformer design could
work for you.

Different connectors, transformers & fuses maybe...
but still the same design.